3-D glass enclosures for electronic devices

ABSTRACT

A 3-D glass enclosure comprises a generally planar glass base member, an encircling glass side wall member connected to the base member, and a generally planar glass cover member connected to the side wall member to form a unitary glass enclosure, the base, sidewall and cover members being made by reforming softened glass sheet preforms and subjecting the reformed members to ion-exchange strengthening, thus providing strong transparent enclosures for electronic devices such as tablet computers, cellphones, media players and televisions.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority under 35 U.S.C. §119 ofU.S. Provisional Application Ser. No. 61/562,622 filed on Nov. 22, 2011,the content of which is relied upon and incorporated herein by referencein its entirety.

BACKGROUND

The products and methods of the present disclosure relate generally toglass enclosures and more particularly to enclosures and enclosureelements for consumer electronic devices such as computers, cellphones,media players, and televisions.

TECHNICAL BACKGROUND

Enclosures for consumer electronic devices are designed to meetstylistic as well as functional requirements. Key functionalrequirements include physical durability and environmental stability,the latter most importantly including resistance to moisture but alsoresistance to electrical, chemical and thermal environmental factors.

At present, meeting all of the requirements for consumer electronicsenclosures involves the mating of diverse glass, metal and plasticenclosure elements. Plastic parts offer a high degree of shapeflexibility and can be designed to provide adequate impact resistancefor some enclosure components, but are highly susceptible to damage fromabrasion. Metals offer good physical durability but are difficult toshape, are prone to scratching and denting damage, and are subject tocorrosion in harsh chemical environments.

Glass imparts the essential characteristic of transparency to advancedconsumer electronics devices, including the vast majority of productsthat increasingly incorporate video display and/or touch screen controlfunctionality as central features. Glass offers a high level ofresistance to chemical attack and scratch-related damage, and inadvanced forms provides reasonable resistance to bending or impactfracture damage as well. Thus it is the preferred construction materialfor video display substrates, protective faceplates for video displays,and touch screen substrates for electronic device control screens.

Notwithstanding the wide range of materials available for the design andconstruction of enclosures for these devices, problems relating toenclosure durability and environmental stability remain. One problem isthat the available materials differ widely in physical and chemicalproperties. Assembling device enclosures from two or more materials ofdiffering thermal expansion, hardness, rigidity, machinability and/orbonding characteristics therefore presents an array of mating problemsthat lead to limits on the ability of the assemblies to retain physicaland environmental integrity over reasonable service lifetimes. Thusthere remains a need for improved enclosure designs of reducedcomplexity as well as improved durability and functional stability.

SUMMARY

The present invention provides electronic device enclosures andcomponents for such enclosures that address many of the above-notedproblems with conventional enclosures. The enclosures of the inventionare formed predominantly of a single construction material, i.e., astrengthened glass, that glass combining high impact resistance withhigh bending strength so as to provide good mechanical durability aswell as transparency and environmental durability. The enclosure designsare three-dimensional (3D), comprising glass front (or top), back (orbottom), and side enclosure members. Enclosures formed primarily ofglass in accordance with the present disclosure can be designed toencase consumer electronic devices ranging in size from cellphones totelevisions, and are particularly well adapted for use in themanufacture of mid-size devices such as laptop or tablet computers whichare presently designed to combine high-definition display and touchscreen control functionality in a single video display faceplate.

In particular embodiments, glass enclosures for electronic devicesprovided in accordance with the present disclosure comprise a generallyplanar glass base member connecting with an encircling glass side wallmember to form a unitary glass container of a predetermined depth. Forthe purposes of the present description “generally planar” membersinclude flat as well as slightly curved sheet structures, slightlycurved meaning embodying large-radius cylindrical or spherical(three-dimensional) curvature as hereinafter more fully described. Agenerally planar glass cover member is permanently bonded to theencircling glass side wall member of the container to form an enclosedvolume of a predetermined depth and of a size and shape selected for theenclosure of an electronic device. Access to the enclosed volume for theinsertion of electronic components is provided by an opening or openingsin the glass side wall member, e.g., by encircling only three of foursides in the case of a square or rectangular enclosure.

The unitary glass container defining the enclosed volume incorporates atleast a first ion-exchanged surface compression layer of a first uniformdepth extending over at least the exterior surface of the container,while the generally planar glass cover member incorporates a secondion-exchanged surface compression layer of a second uniform depthextending over at least the outer surface of the cover. The glassenclosure thus provided is absent major metallic and polymeric enclosingsegments, i.e., segments enclosing more than one side of the enclosure.Thus the use of the latter materials is generally limited to inserts orports providing, for example, speaker openings or plugging interfacesfor electrical power or data connections.

As broadly conceived, a glass enclosure such as above described may beconstructed of three or even more enclosing members. As an example, theunitary glass container may be constructed of separate base and sidewallmembers that are then permanently joined or connected with each othervia organic adhesives or, more advantageously, a glass-to-glass seal, toform the unitary container. For best integrity, however, the inventionprovides enclosure embodiments comprising unitary glass containerswherein the encircling glass sidewall member and glass base member areintegrally connected, i.e., wherein the glass base member is “integralwith” the glass sidewall member, there being no joint or seal betweenthose members. In those embodiments the sidewall portions of thecontainer will merge seamlessly into the glass base portion thereofalong angled or curved edges, as can be achieved, for example, byforming the unitary container from a single glass preform.

In another aspect the invention provides an electronic device comprisingelectronic components contained within an enclosure constructed ofstrengthened glass base, sidewall and cover members as above described,and wherein the electronic components include a video display. Inparticular embodiments of the device, an external surface of at leastone of the base, sidewall, and cover members supports an external touchscreen for controlling one or more functions of the electroniccomponents.

In still another aspect the present invention includes a method formaking a strengthened glass electronic device enclosure. In accordancewith that method, a first softened glass preform, typically a section ofsoftened glass sheet, is formed into a unitary glass containercomprising a generally planar base portion and an encircling sidewallportion integral with the base portion, the sidewall portionadvantageously joining the base portion at curved (rounded) edges. Inparticular embodiments, a softened glass sheet is formed into a unitarycontainer comprising a quadrilateral (e.g. square or rectangular) baseportion and an encircling sidewall portion integral with the baseportion along three of the four edges of the quadrilateral base.

A second softened glass preform is formed into a cover member for thedevice enclosure, that cover member also being of a generally planarconfiguration and a peripheral shape approximately matching the shape ofthe base portion. Again, the generally planar base portion or cover maybe flat or slightly curved, “slight curvature” for the purpose of thepresent description being limited such that the maximum separationbetween the surface of a slightly curved cover or base portion and abase plane defined by the edges of the cover or base portion willgenerally not exceed 10% of the smallest width or breadth of the coveror base.

The unitary glass container and cover member thus provided are subjectedto an ion-exchange strengthening treatment, each such treatmentcomprising exposing the glass part to a source of exchangeable alkalimetal ions for a time and at a temperature sufficient to developstrengthening surface compression layers in each of the glass parts,thus to provide a strengthened glass container and a strengthened glasscover member. The strengthened glass cover member is then attached tothe sidewall portion of the strengthened unitary glass container to theform the strengthened glass enclosure. Any means for attaching the coverto the glass container that can provide a strong, stable andmoisture-impermeable seal between the cover and container can be used.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is further described below with reference to the appendeddrawings, wherein:

FIG. 1 is a photograph presenting a perspective view of a strengthenedglass enclosure; and

FIG. 2 is an illustration of an electronic device comprising astrengthened glass enclosure provided in accordance with an embodimentof the invention.

DETAILED DESCRIPTION

As noted above, particular embodiments of the strengthened glassenclosures provided according to the present invention comprise base andtop members of quadrilateral configuration, as well as embodimentswherein the sidewall member forms at least three sides of aquadrilateral enclosure incorporating such base and top members.

As illustrated in FIG. 1 of the drawings, one embodiments of astrengthened glass enclosure 10 provided in accordance with theinvention may comprise an encircling (u-shaped) strengthened glasssidewall member 12 making up three sides 12 a, 12 b and 12 c of theenclosure, that member being permanently bonded along the three sides toa quadrilateral (rectangular) strengthened glass base member 14 to forma unitary glass container. Sidewall 12 may be permanently bonded to basemember 14 by means, for example, of a cured organic adhesive (e.g., apolymeric seal) or a glass frit seal, not shown, such that a unitaryfour-sided glass container (i.e., comprising the base and three sides)of a predetermined depth D is provided. The sidewall member and baseportions 12 and 14 are subjected separately to an ion-exchangestrengthening treatment prior to assembly where an organic adhesive isto be used for assembling those portions into the container.

Permanently bonded to the upper edges of sides 12 a, 12 b and 12 c toform a strengthened glass enclosure for an electronic device is arectangular strengthened glass cover member 16. Cover member 16 issubjected to an ion-exchange strengthening treatment prior to bonding ifan organic adhesive is employed to form the permanent bond.

A useful organic adhesive for the bonding the base 14 and cover member16 to the sidewall is a UV curable adhesive such as Vitralit® 7105adhesive, commercially available from Panacol-Elosol GmbH,Steinbach/Taunus, Germany. If the glass enclosure is to be assembled andpermanently bonded prior to ion-exchange strengthening, then arefractory inorganic bond of conventional type, such as a glass fritseal, should be used for bonding. For the purposes of the presentdescription the base and cover members may hereinafter beinterchangeably designated as top or front faces and bottom or backfaces, such designations simply depending upon the device to be enclosedand the way in which the enclosed device will be oriented in use.

As further illustrated in FIG. 1, a strengthened glass enclosureproduced as described may be provided with a temporary supporting membersuch as an internal glass or plastic supporting spacer 18. Such a spacermay suitably be of a height corresponding to the predetermined depth Dof the unitary glass container, that depth suitably being in the rangeof 3-50 mm, and may be positioned between the base and cover members,for example proximate to the side opening 18 s of the enclosure, inorder to reduce bending stresses on the adjacent unattached edges 14 aand 16 a of base member 14 and cover member 16. Alternatively or inaddition, a closing and supporting spacer, e.g., a spacer partially ortotally enclosing the side opening not closed by sidewall 12, may beinserted. In some embodiments such a closing spacer may provide speakeropenings or plugging interfaces for the enclosed electronic device.

The development of first and second ion-exchanged surface compressionlayers of a suitable thickness on the surfaces of the glass componentsof the strengthened glass enclosure can be secured through the useion-exchange-strengthenable alkali aluminosilicate glasses. Inparticular embodiments of the disclosed enclosures, each of the firstand second ion-exchanged surface compression layers have a thickness ofat least 30 μm and a peak surface compression level of at least 500 MPa.These levels of surface compression enable the use of glass base,sidewall and cover members of relatively slight thickness, i.e.,thicknesses in the range of 500-2000 μm.

Glasses having good forming capabilities and capable of providingsurface compression layers of adequate stress and thickness via apotassium-for-sodium ion-exchange are known. Examples thereof includealkali aluminosilicate glasses comprising at least about 10% sodiumoxide by weight, in some embodiments 12-15% sodium oxide by weight, andhaving a liquidus viscosity of at least about 1000 Kp, in someembodiments 1000-5000 Kp. Corning Code 2317 and 2318 glasses,commercially available from Corning Incorporated, Corning, N.Y., USA areexamples of suitable glasses. Chemically strengthened enclosurecomponents formed of such glasses can provide excellent transparency aswell as polished surfaces of good optical quality and high resistance tochipping and scratching damage. In addition they can support surfacedecorations or surface coloration or texturing on inner or outersurfaces of the enclosures, such that even low-cost inner surfaceprinting methods can provide permanent decorative features.

The herein-disclosed method for providing a strengthened glass enclosurein accordance with the invention offers particular advantages for theproduction of electronic device enclosures in terms of product integrityand processing efficiency. The advantages of that method result from thefact that the unitary glass container for assembling the enclosure is3D-formed as a one-piece unit by shaping a single softened glass preforminto a container comprising a generally planar base portion integratedwith an encircling sidewall portion. This one-piece unit, together witha planar cover member, is then subjected to ion-exchange strengtheningeither before or after assembly into a completed enclosure dependingupon the particular sealing method to be used.

The glass-forming method employed to form the container and cover is notcritical; any of the known casting, pressing, spinning or blowingmethods could in principle be used. However, in view of the slightthicknesses of the enclosure components to be used, the softened glasspreforms are typically provided in the form of sections of drawn glasssheet of near-optical surface finish, and the shaping of such sheetsections is most efficiently carried out by means of sheet reformingmethods such as pressing or vacuum sagging into molds of a configurationmatching the desired enclosure component. The enclosures can then beassembled from the containers and cover members via conventionalfastening techniques, including for example by metal clipping orpermanent adhesive tape. It is generally desirable to avoidglass-to-glass contact between the containers and covers, and so thin,invisible polymer interfaces can be used permanent frit sealing methodsare not practicable.

For device applications where high mechanical stresses or shock areexpected, enclosure designs providing enhanced stiffness are utilized.As one approach for stiffness enhancement, the U-shaped sidewall memberproviding sides 12 a, 12 b and 12 c of FIG. 1 of the drawings comprisessidewall corners that are smoothly curved into one another, thusexhibiting lower corner stresses under applied strains than those withsharply angled corners. Additional strengthening can be convenientlyprovided in accordance with the above method for one-piece containerforming by using a mold or other shaping means to form a container shapewherein the encircling glass sidewall portion merges into the glass baseportion along curved edges as above described. Curved edges havingcurvature radii in the range of 2-20 mm are suitable for that purpose.

Yet another design choice offering additional enclosure stiffening isthat of adding slight curvature to components of the enclosure. Inparticular embodiments, strengthened glass enclosures are providedwherein at least one of the glass base member or base portion and theglass cover member exhibits slight convex or concave curvature as abovedefined.

FIG. 2 of the drawings presents a perspective view, not in trueproportion or to scale, of an electronic device employing an enclosuredesign incorporating curved enclosure components for added strength asdescribed. In the drawing of FIG. 2, an electronic device 30 comprises astrengthened glass enclosure 20 incorporating an encircling sidewallmember 22 having rounded corners 22 r to reduce sidewall corner stressesas above disclosed. Rounded corners 22 r are curved to match roundedcorners 26 r of cover member 26 which is bonded to sidewall member 22.Also to enhance enclosure rigidity, base portion 24 of enclosure 20merges into and is integral with sidewall portion 22 along rounded edges24 r, and base portion 24 is provided with a slight convex (outward)curvature as indicated by the departure of base portion front edge 24 afrom an imaginary flat base line 24 f and from cover member front edge26 a.

The electronic device 30 of FIG. 2 incorporating glass enclosure 20 asabove configured is a portable media player comprising a video displaycomponent as part of electronic circuitry 40 disposed within theenclosure. Strengthened glass cover member 26 of enclosure providestransparent protection for the display and other components ofelectronic circuitry 40, and also supports a transparent electronictouch screen on its external surface for controlling one or morefunctions of that electronic circuitry.

Strengthened glass enclosures such as provided in accordance with theinvention can be produced over a wide range of sizes and shapesdepending only upon the sizes and shapes of the electronic devices to beenclosed. Enclosure transparency provides an obvious advantage wheneverthe electronic circuitry to be enclosed includes video displaycomponents, while strength and resistance to cosmetic damage favor theiruse for the protection of portable electronic devices, e.g., deviceswherein the enclosed electronic circuitry comprises components for alaptop or tablet computer, a telephone, a camera, or a media player.Enclosures having enclosed volumes in the range of 90-7500 cm³ caneasily accommodate a wide variety of such circuitry. Further, thedesirable electric properties of these glasses make the enclosures wellsuited for the construction of devices wherein at least one of the glassbase member and the glass top member supports an external touch screenfor controlling the electronic circuitry.

While the invention has been described above with respect to particularexamples of materials, designs and methods it will be recognized thatthose examples have been presented for purposes of illustration only,and that a wide variety of other embodiments may adapted to meet theneeds of present or future applications within the scope of the appendedclaims.

What is claimed is:
 1. A glass enclosure for an electronic devicecomprising: a generally planar glass base member connecting with anencircling glass side wall member to form a unitary glass container of apredetermined depth; and a generally planar glass cover memberpermanently connected to the encircling glass side wall member to forman enclosed volume of the predetermined depth; wherein: the unitaryglass container incorporates at least a first ion-exchanged surfacecompression layer of a first uniform depth over at least the exteriorsurface of the container; the generally planar glass cover memberincorporates a second ion-exchanged surface compression layer of asecond uniform depth over at least the outer surface of the covermember; and the glass enclosure is absent metallic and polymericenclosing elements.
 2. A glass enclosure in accordance with claim 1comprising at least one internal glass closing and supporting spacerbonded to at least one of the glass base member and the glass covermember.
 3. A glass enclosure in accordance with claim 1 wherein theglass base member, the encircling glass side wall member, and the glasscover member are formed of alkali aluminosilicate glass of a thicknessin the range of 500-2000 μm.
 4. A glass enclosure in accordance withclaim 1 wherein each of the first and second ion-exchanged surfacecompression layers has a thickness of at least 30 μm and a peak surfacecompression level of at least 500 MPa.
 5. A glass enclosure inaccordance with claim 1 wherein at least one of the glass base memberand the glass cover member exhibits convex or concave curvature.
 6. Aglass enclosure in accordance with claim 1 wherein the predetermineddepth is in the range of 3-50 mm.
 7. A glass enclosure in accordancewith claim 1 wherein the encircling glass sidewall member is integralwith the glass base member and merges into the glass base member alongcurved edges.
 8. A glass enclosure in accordance with claim 7 whereinthe curved edges have curvature radii in the range of 2-20 mm.
 9. Aglass enclosure in accordance with claim 1 wherein the glass base memberis of rectangular shape and wherein the encircling side wall memberforms a u-shaped glass side wall extending from the edges of the glassbase member.
 10. A glass enclosure in accordance with claim 9 whereinthe u-shaped glass sidewall comprises at least two sidewall facesconnecting at a curved corner junction.